Hypoglycemia From Metastatic Meningeal Solitary Fibrous Tumor Occurring Over Two Decades After Initial Diagnosis

Despite multiple intracranial and extracranial relapses associated with a widely metastatic meningeal solitary fibrous tumor (formerly classified as hemangiopericytoma), a 66-year-old type 2 diabetic man was first diagnosed with paraneoplastic hypoglycemia 23 years after the original diagnosis and 12 years after the onset of extracranial metastatic disease. An enlarging mass entirely replacing the left kidney measuring 11.6 × 10 × 28 cm, which had not been locally treated before, was considered to be the putative source of IGF-2 excess. The insulin-like effects of IGF-2 not only ameliorated his long-standing type 2 diabetes mellitus, but also caused spontaneous fasting hypoglycemia. The physiopathology, clinical manifestations, diagnostic approach, and treatment of non-islet cell tumor hypoglycemia are briefly discussed here. Palliative tumor debulking improved the hypoglycemia by day 11 after radiation therapy and glucose monitoring with continuous glucose monitoring system (Dexcom G6) facilitated the patient's management and gave him peace of mind.